The work has been finished since they came here

The work has been finished since they came here It has been 3 years since he came here. Lucy has been cleaning the house since came back home. the work has been finished the work was finished.这两句话 有什么区别吗 the p____ have taken many pictures since they came here The foreigners _____ many places since they came here. five （nine) of the work has been finished. The work has advanced been finished last week. Jim ____ here since he came here.A.has been working B.works finished they has work she find the连词成句 Mr.Smith has been here since the factory opened为 it is two years since I came here还是it has been two years sin